1. Field of the Invention
This invention relates to a plant and method for producing compacted direct reduced iron using iron ore fines as the feedstock and natural gas as the source of reducing gas.
2. Description of the Prior Art
Iron ore reduction processes fall into two ore feedstock and two reduction mechanism categories. Processes which use static or moving beds in shaft furnaces use lump iron ore and iron ore pellets as the feedstock whereas fluid bed processes utilize iron ore fines as the feedstock. The two routes for the reduction of the ores are the production of reducing gas from natural gas by reforming and the direct reduction by carbon containing compounds such as coal.
A number of direct reduction processes have been perfected and have been operated commercially. The majority of plants being installed presently are moving bed systems operating with lump or pellet feedstock and using natural gas to produce the reducing gas by reforming. Iron ore in the form of fines is more plentiful but is only being used as a feedstock in one commercial direct reduction plant at present. This process, which uses fluid beds, has been covered by several patents, among them Ser. No. 07/501,490. The plant, owned by FIOR de Venezuela, has a higher energy consumption than the moving bed processes, and in spite of the lower cost fines feedstock, is not a viable alternative in some situations where energy costs are high.
Accordingly, there is a need to develop a direct reduction process which utilizes more plentiful and cheaper iron ore fines as a feedstock and which has a unit energy consumption similar to that achieved with the shaft furnace moving bed processes. Therefore, energy conservation is achieved by use of this process as compared to existing processes.